Many radio communication systems operate using multiple communication sites that serve specific geographical regions. A subscriber unit operating within such a system typically undergo a registration process in order to facilitate communication within the system. For the system, the registration process provides such information as the identity, configuration, location, and server site for the subscriber unit. Similarly, for the subscriber unit, the registration process provides information about the communication environment and associated parameters.
The communication parameters established during the registration process are subject to change over time. For example, after registration, a mobile subscriber unit may change location and require a new server site. Additionally, the subscriber unit may power down or may otherwise be unavailable to participate in communications. Thus, the information gathered during registration may need to be updated based upon certain circumstances. Many prior art systems perform registration as part of a power up sequence, although registration may be performed under a variety of other conditions. U.S. Pat. No. 5,629,975 issued to Tiedemann, Jr. et al. on May 13, 1997 describes power up, zone based, distance based, timer based, ordered, parameter change, and power down registration.
Depending on system design, registration can be a time consuming process. A subscriber unit may be required to determine available communication sites, to select a server site, to transmit vital communication parameters, and to receive information concerning its environment. While performing these functions, the subscriber unit is usually unavailable for use by a user. It is desirable to minimize the time needed for power up in order to facilitate rapid availability of the subscriber unit. Therefore, a new approach to subscriber registration is needed.